Simulated adipose tissue

1. Technical Field

The present invention relates to simulated adipose tissue.

2. Background Art

Adipose tissue (animal fat) is naturally present in a variety of meat products such as, bacon, steak, chops and roasts. Adipose tissue is also used in a variety of processed meat products, such as, breakfast sausage and meat snacks. The adipose tissue imparts a number of beneficial and highly acceptable properties, such as oil release on cooking and in the mouth. However, the ever diminishing lands available for grazing and growing feed for animals has intensified the search for satisfactory simulated meat products having comparable properties to the natural animal product.

The present invention relates to a simulated adipose tissue which is based on heat coagulable proteinaceous emulsifiers, fibrous proteins and edible lipid material, preferably of non-animal source. The product of this invention has the appearance and properties of adipose tissue and may be used in a variety of food products.

The oil release characteristics of the product are determined by the "fry-away", i.e., the weight loss on frying, which results on frying of slices of the product. The fry-away generally is in the range of about 25 to about 70% by weight.

The non-meat proteinaceous emulsifiers and coagulants used in this invention are constituted by a mixture of precisely limited relative proportions of egg white, gelatin and at least one emulsifying protein isolate.

The proportions of the components which may be used in the simulated adipose material provided in accordance with this invention may vary over a wide range, depending on the desired end properties of the products. The general and preferred ranges are set forth in the following Table I:

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% by weight

Component General Range

Specific Range

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Lipid material about 65 to about 70 to

about 80 about 75

Water about 15 to about 18 to

about 25 about 23

Proteinaceous about 2.5 to about 3.0 to

emulsifiers-overall

about 7.0 about 5.0

Protein isolate

about 1 to about 1.5 to

(dry) about 4 about 2.5

egg white about 1 to about 1 to

about 2.5 about 1.75

gelatin about 0.1 to about 0.3 to

about 1.0 about 0.5

Protein fibres about 15 to about 15 to

about 45 about 20

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The emulsifying protein isolate may be any convenient protein isolate having fat emulsifying properties. It has been found that different protein isolates produce different oil release and texture characteristics, and mixtures of such materials may be used to provide the desired combination of properties. Suitable protein isolates include soy protein isolate and a protein micellar mass (known hereinafter as "PMM").

PMM is a unique protein isolate, the formation of which is described in our Canadian Pat. No. 1,028,552 and involves a controlled two-step operation, in which, in the first step, the protein source material is treated with an aqueous food grade salt solution at a temperature of about 15° to about 35° C., a salt concentration of at least 0.2 ionic strength, generally about 0.2 to about 0.8, and a pH of about 5.5 to about 6.5 to cause solubilization (or salting-in) of the protein, usually in about 10 to about 60 minutes, and, in the second step, the aqueous protein solution is diluted to decrease its ionic strength to a value less than about 0.1.

The dilution of the aqueous protein solution, which may have a protein concentration, for example, up to about 10% w/v, causes association of the protein molecules to form highly proteinaceous micelles which settle in the form of an amorphous highly viscous, sticky, gluten-like micellar mass of protein. The protein micellar mass so produced is referred to herein as PMM and is used to form the protein fibers. The web PMM may be dried to a powder and the drying may be effected in any convenient manner, such as, spray drying, freeze drying or vacuum drum drying.

Improvements in the procedure described in Canadian Pat. No. 1,028,552 may be made to increase the yield of the unique protein isolate from the aqueus protein solution.

The protein materials from which the wet PMM is formed may vary widely and include plant proteins, for example, starchy materials, such as, wheat, corn, oats, rye, barley and triticale; starchy legumes, such as, field peas, chickpeas, fababeans, navy beans and pinto beans; and oil seeds, such as, sunflower seeds, peanuts, rapeseed and soybeans; animal proteins, such as, serum proteins; and microbial protein, i.e., single cell proteins. Preferably, the protein source is a plant material owing to the readily-available nature of these materials.

The mild processing operations effected on the source protein to form the PMM ensure that the protein isolate is in a substantially undenatured form, as determined by differential scanning calorimetry.

Apart from the protein isolate, the remainder of the emulsifier mix is provided by egg white and gelatin. It has been found that all three components are necessary to provide a product having good dimensional stability, good sliceability and good oil release during cooking.

Thus, if gelatin is omitted entirely, the product is soft and non-sliceable whereas if the overall gelatin concentration is too high, then a hard, low oil release product is obtained. Gelatin alone does not produce emulsification.

Similarly, combinations of protein isolate and gelatin alone form products which are soft and lacking in sliceability while egg white and gelatin alone produce a rubbery mass with no fat-like quality and no oil release. All three components, therefore, are required.

The weight ratio of these various proteins at the same overall protein level may be varied considerably to control the final texture from soft to hard. The greater the proportion of egg white present, the drier is the product with less oil release while the greater the proportion of protein isolate present, the more fat-like the product becomes with greater oil release.

The fibrous protein used in the product of this invention may be any conventional texturizing fibrous protein, but preferably is the protein fibres formed from PMM by injection of a PMM into hot water. The fibrous protein provides a structure closely resembling adipose tissue and adds texture, mouth feel and strength to the product.

In addition, the protein fibres increase the overall protein content of the product while the fibres do not significantly decrease oil release on cooking although some decrease in oil release is experienced with increasing concentrations of fibres. The fibres, therefore, represent a substantially inert protein filler with respect to fat binding. The presence of the protein fibres thus enables the overall protein level of the product after oil release on cooking to increase to a high level, for example, about 15 to about 30 wt.%, without resulting in a cake-like texture and without having to use high cost protein materials.

Protein fibres of various dimensions may be employed in the product of the invention, generally of length of about 0.5 to about 15 cm, preferably about 1 to about 4 cm, and of diameter of about 0.1 to about 1 mm. Mixtures of fibres of differing dimensions may be used to provide variable texture.

The edible lipid material may be any convenient edible lipid material capable of emulsification in water with the mixture of emulsifiers and is usually at least one edible oil, preferably from a non-animal source, such as a vegetable oil, which may be unsaturated.

The simulated adipose tissue is formed by dissolving and/or dispersing the proteinaceous emulsifiers in water, emulsifying the edible lipid material with the proteinaceous dispersion, incorporating the fibrous protein in the emulsion in dispersed form, and then heat setting the emulsion to a fat-like solid material consisting of a heat-coagulated matrix of protein with entrapped lipid material having protein fibres dispersed therethrough.

The fibrous protein may be incorported into the emulsion in any convenient manner, such as by direct addition thereto or by dispersing the same in the aqueous emulsifier dispersion. It is usually preferred to add the fibres to the emulsion to avoid degradation under the usually high shear conditions of emulsion formation.

The degree of emulsification achieved and hence the final texture of the product can be controlled to a certain degree by variation of certain parameters during the emulsification step.

For example, the pH of the emulsifier dispersion can affect the emulsification capacity of the proteins. The aqueous dispersion, therefore, is usually adjusted, if necessary, to a pH of about 6.5 to about 8.0, preferably about 7.0 to about 7.6, prior to commencing emulsification.

Variations in the temperature at which emulsification occurs also varies the degree of emulsification, with greater emulsification occurring at 40° C. than at ambient temperature (20° to 25° C.). This difference in emulsification leads to a higher oil release from a product produced at a higher emulsification temperature.

The presence or absence of sodium chloride also has an effect on emulsification. Since sodium chloride tends to increase dispersion of the proteins and the more dispersed the proteins, the more available they are for emulsification, it is preferred to provide small amounts, generally up to about 3.5% by weight, preferably about 1 to about 2.5% by weight.

The emulsification is usually effected under conditions of high shear for at least part of the procedure, although high shear can lead to over emulsification and destabilization if prolonged. Usually, a high shear mixing of about 5 to 15 minutes is adopted with a final low shear mixing being effected for about 5 to 15 minutes.

Depending on the desired end use of the simulated adipose tissue, flavourings of any type may be incorporated into the product by inclusion of the same in the emulsion prior to heat setting.

The emulsion is heat set by heating to an elevated coagulating temperature, generally in the range of about 90° to about 120° C. with a superatmospheric pressure being applied, if necessary, at the upper end of this range. It has been found that the texture of the product varies with the coagulating temperature, with a firmer product being obtained at the higher temperatures.

The simulated adipose material provided in accordance with this invention has the appearance and feel of adipose tissue and exhibits fat release on cooking so that no additional oil is required. The product also exhibits fat release in the mouth which together with the fibrous texture give a good mouthfeel to products incorporating the simulated adipose material.

The simulated adipose tissue of this invention may be used in a variety of products as a simulated meat fat material, such as in chunk form in various food products, such as meat snacks and dried sausages, or as the white phase of a bacon analog material.

In U.S. Pat. No. 3,840,677, assigned to General Foods Corporation, there is described a bacon analog product comprising a fatty or white phase and a lean or red phase. A new bacon analog product is provided by a combination of the simulated adipose tissue of this invention as the white phase and a red phase having the composition set forth in the U.S. patent, as outlined in the following Table II:

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% by weight

Component General Range

Preferred Range

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Water about 40 to about 45 to

about 65 about 60

Fat about 10 to about 15 to

about 25 about 25

Protein isolate

about 6 to about 9 to

about 24 about 18

Albumen up to about 15

about 1 to

about 8

Proteinaceous 0 to about 15

about 1 to

filler about 10

Colour and to taste (usually

about 5 to

flavouring 5 to 15) about 10

agents

Thickening agent

0 to about 2 0 to about 1

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As described in the prior patent, a bacon analog product is obtained by layering emulsions corresponding to the red phase and white phase in the desired thickness and then heat coagulating the layered emulsions. The resulting coagulated material has good sliceability and is sliced to the desired thickness.

The use of the simulated adipose material of this invention as the white phase results in a simulated bacon analog which crinkles and has good texture on cooking, and has good oil release for frying without added cooking oil or fat.

The invention is illustrated by the following examples:

This Example illustrates the formation of a simulated adipose tissue in accordance with this invention and the use thereof in a bacon analog.

A formulation for the simulated adipose tissue was chosen, as follows:

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Component Wt. %

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Fababean PMM 2.50

Egg white solids 1.00

Gelatin 0.33

Sodium chloride 2.00

Water 21.50

Vegetable oil 72.67

100.00%

Protein fibres 30 wt. % of

above

Spices and flavours

as required

for taste

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The fababean PMM (i.e., a PMM prepared from fababeans in accordance with the process of Canadian Pat. No. 1,028,552) was dispersed with sodium chloride in 80% of the water, the pH was adjusted to about 7.6, and the mixture was solubilized for 30 minutes. The gelatin was dispersed in the remaining 20% of the water, heated to about 40° C. to solubilize the same and cooled to about 30° C. prior to addition to the fababean PMM dispersion. The egg white solids were then added to the protein mixture, the pH again adjusted to about 7.6, and the mixture was solubilized for about 15 minutes.

Rehydrated (in water) thawed fresh fababean PMM fibres of diameter about 0.4 mm and length of about 0.5 to about 2 cm were added to the solubilized mixture along with water soluble spices and flavours. Two-thirds of the oil was then blended (or homogenized) with the protein and fibre mixture at high shear for 10 minutes after first dissolving oil soluble flavours in the oil.

The mixture was transferred to a Hobart Kitchen Aid™ mixer, and the remaining oil was blended in at speed 8 to 10 minutes. The resulting emulsion was layered into pans with lean phase bacon analog as described in U.S. Pat. No. 3,840,677 and heat set for 1 hour in flowing steam. The heat-set slab then was tempered for 12 to 24 hours at about 4° C.

The tempered slab was sliced to desired thickness and fried at 177° C. (350° F.) for time varying from 4 to 8 minutes providing different final doneness and texture. No oil was added and satisfactory oil release was observed. The cooked bacon analog exhibited good taste characteristics, as compared with natural bacon.

In summary of this disclosure, the present invention provides a simulated adipose tissue having many desirable properties and wide utility. Modifications are possible within the scope of this invention.